151 строка
4.1 KiB
C
151 строка
4.1 KiB
C
/*
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* Marvell Orion SoC timer handling.
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*
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* Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
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*
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* This file is licensed under the terms of the GNU General Public
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* License version 2. This program is licensed "as is" without any
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* warranty of any kind, whether express or implied.
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*
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* Timer 0 is used as free-running clocksource, while timer 1 is
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* used as clock_event_device.
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*/
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#include <linux/kernel.h>
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#include <linux/bitops.h>
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#include <linux/clk.h>
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#include <linux/clockchips.h>
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#include <linux/interrupt.h>
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#include <linux/of_address.h>
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#include <linux/of_irq.h>
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#include <linux/spinlock.h>
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#include <linux/sched_clock.h>
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#define TIMER_CTRL 0x00
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#define TIMER0_EN BIT(0)
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#define TIMER0_RELOAD_EN BIT(1)
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#define TIMER1_EN BIT(2)
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#define TIMER1_RELOAD_EN BIT(3)
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#define TIMER0_RELOAD 0x10
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#define TIMER0_VAL 0x14
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#define TIMER1_RELOAD 0x18
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#define TIMER1_VAL 0x1c
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#define ORION_ONESHOT_MIN 1
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#define ORION_ONESHOT_MAX 0xfffffffe
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static void __iomem *timer_base;
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static DEFINE_SPINLOCK(timer_ctrl_lock);
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/*
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* Thread-safe access to TIMER_CTRL register
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* (shared with watchdog timer)
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*/
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void orion_timer_ctrl_clrset(u32 clr, u32 set)
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{
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spin_lock(&timer_ctrl_lock);
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writel((readl(timer_base + TIMER_CTRL) & ~clr) | set,
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timer_base + TIMER_CTRL);
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spin_unlock(&timer_ctrl_lock);
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}
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EXPORT_SYMBOL(orion_timer_ctrl_clrset);
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/*
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* Free-running clocksource handling.
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*/
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static u32 notrace orion_read_sched_clock(void)
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{
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return ~readl(timer_base + TIMER0_VAL);
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}
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/*
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* Clockevent handling.
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*/
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static u32 ticks_per_jiffy;
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static int orion_clkevt_next_event(unsigned long delta,
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struct clock_event_device *dev)
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{
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/* setup and enable one-shot timer */
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writel(delta, timer_base + TIMER1_VAL);
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orion_timer_ctrl_clrset(TIMER1_RELOAD_EN, TIMER1_EN);
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return 0;
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}
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static void orion_clkevt_mode(enum clock_event_mode mode,
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struct clock_event_device *dev)
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{
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if (mode == CLOCK_EVT_MODE_PERIODIC) {
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/* setup and enable periodic timer at 1/HZ intervals */
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writel(ticks_per_jiffy - 1, timer_base + TIMER1_RELOAD);
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writel(ticks_per_jiffy - 1, timer_base + TIMER1_VAL);
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orion_timer_ctrl_clrset(0, TIMER1_RELOAD_EN | TIMER1_EN);
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} else {
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/* disable timer */
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orion_timer_ctrl_clrset(TIMER1_RELOAD_EN | TIMER1_EN, 0);
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}
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}
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static struct clock_event_device orion_clkevt = {
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.name = "orion_event",
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.features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
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.shift = 32,
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.rating = 300,
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.set_next_event = orion_clkevt_next_event,
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.set_mode = orion_clkevt_mode,
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};
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static irqreturn_t orion_clkevt_irq_handler(int irq, void *dev_id)
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{
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orion_clkevt.event_handler(&orion_clkevt);
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return IRQ_HANDLED;
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}
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static struct irqaction orion_clkevt_irq = {
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.name = "orion_event",
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.flags = IRQF_TIMER,
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.handler = orion_clkevt_irq_handler,
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};
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static void __init orion_timer_init(struct device_node *np)
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{
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struct clk *clk;
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int irq;
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/* timer registers are shared with watchdog timer */
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timer_base = of_iomap(np, 0);
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if (!timer_base)
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panic("%s: unable to map resource\n", np->name);
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clk = of_clk_get(np, 0);
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if (IS_ERR(clk))
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panic("%s: unable to get clk\n", np->name);
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clk_prepare_enable(clk);
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/* we are only interested in timer1 irq */
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irq = irq_of_parse_and_map(np, 1);
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if (irq <= 0)
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panic("%s: unable to parse timer1 irq\n", np->name);
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/* setup timer0 as free-running clocksource */
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writel(~0, timer_base + TIMER0_VAL);
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writel(~0, timer_base + TIMER0_RELOAD);
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orion_timer_ctrl_clrset(0, TIMER0_RELOAD_EN | TIMER0_EN);
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clocksource_mmio_init(timer_base + TIMER0_VAL, "orion_clocksource",
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clk_get_rate(clk), 300, 32,
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clocksource_mmio_readl_down);
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setup_sched_clock(orion_read_sched_clock, 32, clk_get_rate(clk));
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/* setup timer1 as clockevent timer */
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if (setup_irq(irq, &orion_clkevt_irq))
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panic("%s: unable to setup irq\n", np->name);
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ticks_per_jiffy = (clk_get_rate(clk) + HZ/2) / HZ;
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orion_clkevt.cpumask = cpumask_of(0);
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orion_clkevt.irq = irq;
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clockevents_config_and_register(&orion_clkevt, clk_get_rate(clk),
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ORION_ONESHOT_MIN, ORION_ONESHOT_MAX);
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}
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CLOCKSOURCE_OF_DECLARE(orion_timer, "marvell,orion-timer", orion_timer_init);
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